Air moving devices such as fans and blowers are an important aspect of cooling and/or ventilation systems, such as the cooling systems employed in today's electronic devices, systems, etc. (e.g., computer devices such as central processing units (CPUs), server devices, storage devices, video cards, and the like). In the case of electronic devices, systems, etc., such air moving devices are typically used to push and/or draw air across heat sinks, in order to remove waste heat from components of these electronic devices, systems, and the like.
Control circuitry is often employed to control one or more aspects of the operation of these air moving devices, particularly in situations where cooling and/or ventilation systems include a plurality of air moving devices. It has been recognized that significant benefits can be gained from controlling aspects of the operation of air moving devices. For example, control circuitry may be employed to influence the speed of an air moving device in response to the ambient temperature inside an electronic device or system (e.g., after a decrease in ambient temperature is detected, the speed of the air moving device is decreased). As a result, the air moving device may be operated at less than its maximum abilities, while still meeting any device or system cooling specifications. By operating an air moving device below its maximum abilities, significant audio noise reduction and power consumption reduction can be achieved. In addition, the ability to operate the air moving device at a less than maximum speed, while still meeting any cooling and/or ventilating specifications, also reduces wear to the air moving device.
It has also been recognized that by synchronizing all of the air moving devices in a multiple-air moving device system, device-to-device beat frequencies can be eliminated. In addition, device synchronization provides reduced perceived audio noise, reduced chassis vibration modes, more uniform air flow, and constant air flow over time and air moving device aging.
Typically the above discussed control circuitry is located on the main printed circuit board (PCB) situated inside the electronic device, system, etc., the one or more air moving devices are employed to cool and/or ventilate. Normally, this centralized control circuitry controls all air moving devices within the electronic device or system. One undesirable side effect of such centralized control circuitry is a lack of redundancy. For example, in at least some instances, if the central control circuitry fails for some reason, so to do all of the air moving devices of the cooling system.
Another notable disadvantage of such centralized circuitry is that it occupies valuable system or device space. Space within an electronic device and/or system is scarce. Therefore, centralized control circuitry, or any circuitry extending beyond the volume/profile of the air moving device(s), takes up electronic device or system space that could be otherwise occupied by other circuits, components, etc. As a result, system or device design is often comprised to accommodate such centralized control circuitry.
In response to this lack of redundancy and/or scarcity of space, some air moving device manufacturers have attempted to localize the control circuitry to the air moving device. For example, at least one manufacturer has begun incorporating control circuitry onto a PCB, which is disposed inside the hub of an air moving device.
Incorporating control circuitry into the hub of an air moving device, however, presents at least a few problems. First, in some circumstances, the control circuitry needed to facilitate all of the desired functions for an air moving device may be too large to incorporate into the hub of the air moving device. In addition, incorporating control circuitry into the hub of an air moving device normally takes cooperation between an air moving device manufacturer and a control circuitry manufacturer. For example, oftentimes, the control circuitry manufacturer must first find a device manufacturer willing to incorporate the circuit manufacturer's control circuitry into at least one of the device manufacturers' air moving devices. Furthermore, if the circuit manufacturer is able to find such a device manufacturer, oftentimes the control circuitry, as well as where the control circuitry is disposed within an air moving device, must be developed to the device manufacturer's specific air moving device. Therefore typically, the control circuitry cannot be deployed with other manufacturers' air moving devices. As a result, an undesirable single customer and/or supplier scenario arises for the circuit manufacturer. Furthermore, if an air moving device manufacturer does not want to incorporate control circuitry into the hub of the air moving device, an off the shelf version of the air moving device can not be easily converted into a device having control circuitry in its hub. In addition to the above, air moving devices having control circuitry in their hubs are relatively more expensive than fans not including such circuitry.